Electrode assembly for arc welding

ABSTRACT

The disclosed technology generally relates to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding. In one aspect, an electrode assembly for submerged arc welding comprises a contact tip portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough. During welding, the contact tip portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode. The extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material surrounding the consumable electrode.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

This application claims the benefit under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 63/264,358, entitled ELECTRODEASSEMBLY FOR ARC WELDING, filed Nov. 19, 2021, and to U.S. ProvisionalPatent Application No. 63/370,430, entitled ELECTRODE ASSEMBLY FOR ARCWELDING, filed Aug. 4, 2022. The entirety of each of the aboveapplications is hereby incorporated by reference herein.

BACKGROUND Field

The disclosed technology generally relates to welding technologies andmore particularly to electrode assemblies for arc welding, e.g.,submerged arc welding.

Description of the Related Art

Various welding technologies utilize welding wires that serves as asource of metal. For example, in metal arc welding, an electric arc iscreated when a voltage is applied between a consumable weld electrodewire, which serves as one electrode that advances towards a workpiece,and the workpiece, which serves as another electrode. The arc melts atip of the metal wire, thereby producing droplets of the molten metalwire that deposit onto the workpiece to form a weldment or weld bead.

Technological and economic demands on welding technologies continue togrow in complexity. For example, the need for higher bead quality inboth appearance and in mechanical properties continues to grow,including high yield strength, ductility and fracture toughness.Simultaneously, the higher bead quality is often demanded whilemaintaining economic feasibility. Some welding technologies aim toaddress these competing demands by improving the consumables, e.g. byimproving the physical designs and/or compositions of the electrodewires.

Submerged arc welding (SAW) can provide highly economic solutions forsome applications. The high deposition rates attained with submerged arcare chiefly responsible for the economies achieved with the process.

SUMMARY OF THE INVENTION

In an aspect, an electrode assembly for submerged arc welding (SAW)comprises a head portion and an extension portion arranged serially andconfigured to feed a consumable electrode therethrough, wherein duringwelding, the head portion is disposed to be distal to an arcing tip ofthe consumable electrode and the extension portion is disposed to beproximal to the arcing tip of the consumable electrode. The extensionportion is elongated in a wire feed direction and is configured toelectrically insulate the consumable electrode from a work piece duringwelding with an insulating sleeve surrounding the consumable electrode.The electrode assembly is configured such that, during SAW withconsumable electrode inserted therethrough, a ratio between anelectrical stick-out distance, which is measured between a contact tipportion disposed at an end of the head portion and the arcing tip of theconsumable electrode, and a diameter of the electrode exceeds 30.

In another aspect, an electrode assembly for submerged arc welding,comprises a head portion and an extension portion arranged serially withthe head portion, wherein the head portion and the extension portion areconfigured to feed a consumable electrode therethrough. The extensionportion is configured to be disposed closer to an arcing tip of theconsumable electrode relative to the head portion and comprises anenvelope formed of a nonmagnetic material and an insulating sleevedisposed within the envelope and comprising a solid insulating materialconfigured to surround the consumable electrode.

In another aspect, an extension portion configured for a submerged arcwelding electrode assembly comprises an envelope formed of a nonmagneticmaterial and an insulating sleeve disposed within the envelope andcomprising a solid insulating material configured to surround aconsumable electrode. The extension portion is configured to be arrangedserially with a head portion of the electrode assembly and to receive aconsumable electrode from the head portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a submerged arc welding (SAW) systemaccording to embodiments of the present technology.

FIG. 2 illustrates a conventional electrode assembly for a SAW system.

FIG. 3A illustrates a conventional electrode assembly for a SAW systemover a workpiece having a shallow groove.

FIG. 3B illustrates a long stick-out (LSO) electrode assembly for a SAWsystem over a workpiece having a shallow groove.

FIG. 4A illustrates a conventional electrode assembly for a SAW systemover a workpiece having a deep groove.

FIG. 4B illustrates an LSO electrode assembly for a SAW system over aworkpiece having a deep groove.

FIG. 5 is a graph showing an experimental comparison of deposition ratesversus current for both conventional SAW assemblies and LSO SAWassemblies.

FIGS. 6A-6C depict perspective views of an LSO electrode assembly havingan extension portion according to embodiments of the present technology.

FIG. 7A is an isometric view of an LSO extension portion according toembodiments of the present technology.

FIG. 7B is an exploded view of the LSO extension portion depicted inFIG. 7A.

FIG. 7C is a perspective view of an envelope or nozzle body for an LSOextension portion according to embodiments of the present technology.

FIG. 7D is a cross-sectional view of the envelope or nozzle bodydepicted in FIG. 7C taken along line A-A.

FIG. 7E depicts a perspective view of an insulating sleeve for an LSOextension portion according to embodiments of the present technology.

FIG. 7F is a cross-sectional view of the nozzle body depicted in FIG. 7Etaken along line B-B.

FIG. 8 is a cross-sectional view of an LSO extension portion accordingto embodiments of the present technology.

FIGS. 9A and 9B show multi-arc LSO SAW assemblies according toembodiments of the present technology.

DETAILED DESCRIPTION

In processes using a consumable electrode, the electrode or the wiremelts to provide an additive metal that fills a gap to form a weld jointthat joins two metal workpieces. The welding processes using consumableelectrodes include shielded metal arc welding (SMAW), gas metal arcwelding (GMAW) or metal inert gas (MIG) welding, flux-cored arc welding(FCAW), metal-cored arc welding (MCAW), and submerged arc welding (SAW),among others.

Submerged Arc Welding

FIG. 1 schematically illustrates a submerged arc welding (SAW) system100 for depositing a filler or weld metal onto a workpiece 102. Thesystem 100 includes a bare metal electrode wire 104 having a tip 106, acontact tip 110 coupled to the electrode 104, and a power supply 108,which is electrically coupled to the contact tip 110 and the workpiece102. The system 100 also includes a flux delivery system 112, which isconfigured to dispense flux 114 onto the workpiece 102 during the SAWprocess. The electrode 104 generally comprises a metal or alloy whilethe flux comprises granular fusible material. During the SAW process,heat is derived from an arc 116 between a bare metal electrode 104 and aworkpiece 102. The arc is shielded by a blanket of the flux 114 which isplaced over the joint area ahead of the arc 116. Filler metal isobtained primarily from the electrode wire 104 which is continuously fedthrough the blanket of flux 114 into the arc 116 and pool 122 of moltenflux. Additional filler metal may be obtained by adding cold wire to theweld pool 122 or from metal powder contained in the flux 114.Accordingly, in SAW, unlike the other fluxed processes, two consumables(the electrode wire 104 and the flux 114) are used and these twoconsumables may be supplied separately.

The distinguishing feature of SAW is the flux 114, which covers the weldarea and prevents arc radiation, sparks, spatter and fumes fromescaping. The flux 114 allows for achieving high deposition rates andhigh quality weld deposit characteristics. In addition to shielding thearc 116 from view, the flux 114 provides a slag 118 which protects theweld metal 120 as it cools, deoxidizes and refines the weld metal 120,insulates the weld to reduce the cooling rate and helps shape the weldcontour.

During the SAW process, the heat of the arc 116 melts some of the flux114 along with the tip 106 of the electrode 104 to form a weld pool 122,as illustrated in FIG. 1 . The tip 106 of the electrode 104 and thewelding zone are always surrounded and shielded by molten flux 114,which is itself covered by a layer of unfused flux 114. The electrode104 is held a short distance above the workpiece 102 with the arc 116forming between the electrode 104 and the workpiece 102. As theelectrode 104 progresses along the joint, the lighter molten flux 114rises above the molten metal in the weld pool 122 as slag 118. Themolten metal in the weld pool 122, which has a higher melting (freezing)point, solidifies while the slag 118 above it is still molten. The slag118 then freezes over the newly solidified weld metal 120, continuing toprotect the metal 120 from contamination while it is very hot and wouldreact with atmospheric oxygen and nitrogen. After cooling and removingany unfused flux 114 for reuse, the solidified slag 118 may be easilyremoved from the weld.

The power supply 108 generates a voltage and current for the system 100and the voltage and current are applied to the workpiece 102 and theelectrode 104. The current is applied to the electrode via the contacttip 110. High currents can be used in submerged arc welding andextremely high heat can be generated. Because the current is applied tothe electrode 104 a short distance above its tip 106, relatively highamperages can be used on small diameter electrodes. This results inextremely high current densities on relatively small cross sections ofelectrode. Currents as high as or exceeding 600 amperes can be carriedon electrodes as small as 64″, giving a density in the order of 100,000amperes per square inch six to ten times that carried on stickelectrodes.

Because of the high current density, the melt off rate is much higherfor a given electrode diameter than with stick-electrode welding. Themelt-off rate is affected by the electrode material, the flux 114, typeof current, polarity, and length of wire beyond the point of electricalcontact in the gun or head.

Submerged arc welding may be performed with either DC or AC power.Direct current gives better control of bead shape, penetration, andwelding speed, and starting is relatively easier. Bead shape is usuallybest with DC electrode positive (DCEP or reverse polarity), which alsoprovides maximum penetration. Highest deposition rates and minimumpenetration can be obtained with DC electrode negative (DCEN).Alternating current minimizes arc blow and gives penetration betweenthat of DCEP and DCEN.

The insulating blanket of flux 114 above the arc 116 prevents rapidescape of heat and concentrates it in the welding zone. Not only are theelectrode 104 and base metal of the workpiece 102 melted rapidly, butthe fusion is deep into the base metal. The deep penetration allows theuse of small welding grooves, thus minimizing the amount of filler metalper foot of joint and permitting fast welding speeds. Fast welding, inturn, minimizes the total heat input into the assembly and, thusminimizes problems of heat distortion. Even relatively thick joints canbe welded in one pass by submerged arc welding.

Welds made under the protective layer of flux 114 have good ductilityand impact resistance and uniformity in bead appearance. Mechanicalproperties at least equal to those of the base metal are consistentlyobtained. In single-pass welds, the fused base material is largecompared to the amount of filler metal used. Thus, in such welds thebase metal may greatly influence the chemical and mechanical propertiesof the weld. For this reason, it is sometimes unnecessary to useelectrodes of the same composition as the base metal for welding many ofthe low-alloy steels. However, the chemical composition and propertiesof multipass welds are less affected by the base metal and depend to agreater extent on the composition of the electrode, the activity of theflux, and the welding conditions.

Through regulation of current, voltage, and travel speed, the operatorcan exercise close control over penetration to provide any depth rangingfrom deep and narrow with high-crown reinforcement, to wide, nearly flatbeads with shallow penetration. Beads with deep penetration may containon the order of 70% melted base metal, while shallow beads may containas little as 10% base metal. In some instances, the deep-penetrationproperties of submerged arc welding can be used to eliminate or reducethe expense of edge preparation.

The flux serves several functions in submerged arc welding. Theseinclude covering the molten weld metal to protect it from the atmosphereand acting as a slag which refines the molten deposit by scavengingoxides and other non-metallic inclusions. Metallic additions to the fluxcan add to the alloy content of the deposit and deoxidize it.

There are four types of fluxes based on their method of manufacture;fused, bonded, agglomerated and mechanically mixed.

Fluxes are also identified as basic, acid, and neutral. Basic fluxescontain oxides of metals which dissociate easily while acidic fluxescontain oxides which dissociate to a small extent. A neutral flux doesnot add or subtract from the composition of the weld deposit. Fluxeshaving a ratio of CaO or MnO to SiO₂ which is greater than one areconsidered basic, those near one are considered neutral, and those lessthan one are acidic.

With proper selection of equipment, submerged arc is widely applicableto the welding requirements of industry. It can be used with all typesof joints, and permits welding a full range of carbon and low alloysteels, from 16-gage sheet to the thickest plate. It is also applicableto some high-alloy, heat-treated, and stainless steels, and is a favoredprocess for rebuilding and hard surfacing. Any degree of mechanizationcan be used—from the hand-held semi-automatic gun to boom ortrack-carried and fixture held multiple welding heads.

The high quality of submerged arc welds, the high deposition rates, thedeep penetration, the adaptability of the process to full mechanization,and the comfort characteristics (no glare, sparks, spatter, smoke, orexcessive heat radiation) make it a preferred process in steelfabrication. It is used extensively in ship and barge building, railroadcar building, pipe manufacture, and in fabricating structural beams,girders, and columns where long welds are required. Automatic submergedarc installations are also key features of the welding areas of plantsturning out mass-produced assemblies joined with repetitive short welds.

Other factors than deposition rates enter into the lowering of weldingcosts. Continuous electrode feed from coils, ranging in weight from 60to 1,000 pounds, contributes to a high operating factor. Where thedeep-penetration characteristics of the process permit the eliminationor reduction of joint preparation, expense is reduced. After the weldhas been run, cleaning costs are minimized, because of the eliminationof spatter by the protective flux.

When submerged-arc equipment is used properly, the weld beads are smoothand uniform, so that grinding or machining are rarely required. Sincethe rapid heat input of the process minimizes distortion, the costs forstraightening finished assemblies are reduced, especially if a carefullyplanned welding sequence has been followed. Submerged arc welding, infact, often allows the pre-machining of parts, further adding tofabrication cost savings.

Because of these and other advantages provided by SAW, there is a desireand need to further improve various aspects of SAW, including evenhigher productivity and weld quality. For example, as one of thetechnical advantages of SAW derives from preheating the consumableelectrode, there is a desire and need to further improve the preheatingarrangement through improved electrode assembly design.

Long Stick-Out Electrode Assembly for Submerged Arc Welding

FIG. 2 illustrates an electrode assembly 200 defining an electricalstick-out and positioned over a workpiece 202. The electrode assembly200 includes a head portion 204 configured to receive a consumableelectrode 206. The head portion 204 includes a contact tip 210, anelectrode guide tube 212, and an insulated guide 214. The contact tip210 is disposed radially around the electrode 210 and is configured totransfer current from a power source (e.g., power source 108 shown inFIG. 1 ) to the electrode 206. The electrode 206 includes a tip portion208 configured to extend beyond the head portion 204. The portion of theelectrode 206 that extends between the end portion 208 and the end ofthe head portion 204 is referred to as the visible stick-out 218 whilethe portion of the electrode 206 that extends between the tip portion208 and the contact tip 210 is referred to as the electrical stick-outor electrical electrode extension 216. Unless stated otherwise, astick-out length as used herein refers to the length of the electricalstick-out 216, which is the parameter predominantly affecting theelectrical response of the electrode assembly 200. During operation ofthe electrode assembly 200, the tip portion 208 is positioned adjacentto the workpiece 202 and the distance between the contact tip 210 andthe workpiece 202 is referred to as the contact tip to work distance(CTWD) 220.

The electrical stick-out 216 of the electrode wire 206 is preheated byJoule heating. If the electrical electrode extension 216 is notsufficiently long, the electrode wire 206 may not be sufficientlypreheated. On the other hand, an increase of the length of theelectrical stick-out 216 increases the electrical resistance of thecircuit, which in turn increases the heating and hence the temperatureof the tip 208 of the electrode 206, leading to increased melting anddeposition rate. The length of the electrical stick-out 216 in turncontrols the dimensions of the weld bead since the length of the fillerwire extension affects the burn-off rate. Further, electrical electrodeextension 216 exerts an influence on penetration through its effect onthe welding current. As the length of the electrical electrode extension216 is increased, the preheating of and the voltage drop across theelectrode wire 206 increases. The greater voltage drop can result in thebead shape being more convex, which can be overcome by increasing theinput voltage by 2-5 volts. The length of the electrical stick-out 216distance can be approximately 3-10 times a diameter of the electrode 206depending on the type of steel being welded, for traditional steelwelding processes.

FIG. 3A depicts an electrode assembly 300A positioned over a workpiece302 having a groove 303. In the illustrated configuration, the stick-outportion 316A of the electrode 306A extends a conventional distancebeyond the contact tip 310A (e.g., 3 to 12 times the diameter of theelectrode). The electrode assembly 300A is positioned such that the headportion 304A is positioned over the groove 303 and the tip 308A of theelectrode 308A is within the groove 303. More specifically, the headportion 304A is positioned such that the tip 308A is adjacent to thebottom of the groove 303 without the head portion 304A contacting theworkpiece 302. In the illustrated embodiment, the tip 308A is positionedwithin the groove such that the CTWD 320A is about 25 mm. Positioningthe tip 308A closely adjacent to the bottom of the groove 303 allows forbetter and more consistent arcing between the tip 308A and the workpiece302, thereby resulting in a more consistent deposition of filler metalinto the groove 303 and improved weld quality and efficiency.

To further improve upon submerged arc welding (SAW) technology, a longstick-out (LSO) or extended stick-out technology developed by LincolnElectric company may be employed. Long stick-out SAW refers to SAWprocesses in which the length of the wire that sticks out (“stick-outlength”) of the electrode contact tip, or the contact-to-work distance(CTWD), is increased relative to conventional SAW processes, e.g.,longer than about 25 mm. As used herein, LSO refers to an electrodeconfiguration in which the electrical stick out exceeds about 10 times adiameter of the electrode 306A. The longer stick-out length allows for agreater length of the electrode to be preheated prior to melting at theelectrode tip. The preheating allows for melt-off rate to increase as aresult, as it is easier to melt a preheated electrode wire for a givencurrent density. The LSO SAW process can provide significant improvementin productivity and can provide up to 100% increase in submerged arcwelding deposition rates over traditional SAW processes. The LSO SAWprocess can reduce or eliminate arc striking problems by allowingcomplete tailoring of the arc start characteristics. The LSO SAW canalso provide improved control over the input of energy into the weld,lower heat input (less distortion), flux/wire ratio reduction.

FIG. 3B depicts an electrode assembly 300B positioned over the groove303 in workpiece 302. The electrode assembly 300B employs an LSOtechnology such that the electrical stick-out 316B extends beyond thecontact tip 310B by substantially more than the stick-out 316A extendingbeyond the contact tip 310A (FIG. 3A). For example, in some embodiments,the stick-out 316B can have a length between 10 and 40 times thediameter of the electrode 308B. In some embodiments, the stick-out 316Bcan have a length that is more than 40 times the diameter of theelectrode 308B. The increased length of the stick-out portions 316Ballows for a greater length of the electrode 306B to be preheated priorto melting at the electrode trip, thereby allowing for increasedmelt-off and deposition rates, as explained above.

The increased length of the stick-out portions in LSO SAW systems alsoallows for the LSO systems to be used to easily fill grooves thatconventional SAW systems are either incapable of filling or can onlyfill using extremely precise arrangements and high operator skill.Specifically, while conventional SAW systems can be used with wideand/or short grooves, conventional SAW systems typically cannot beeasily used with deeper and/or narrower grooves. FIGS. 4A and 4B depictelectrode assemblies 400A, 400B positioned over a workpiece 402, wherethe electrode assembly 400A is generally similar to the assembly 300Ashown above in connection with FIG. 3A and electrode assembly 400B isgenerally similar to the assembly 300B shown in above in connection withFIG. 3B. The workpiece 402 has a groove 403 which is substantiallydeeper and narrower than the groove 303 shown in above in FIGS. 3A and3B. Accordingly, when the assemblies 400A and 400B are placed over thegroove 403, the head portions 404A, 404B are positioned further from thebottom of the groove, resulting in the CTWD 420 being substantiallylonger than 25 mm. For example, in some embodiments, the CTWD or theelectrical stick-out can be 125 mm or longer. When the electrodeassembly 400A is positioned over the workpiece 402 such that the tip408A is within the groove 403, the size and shape of the head portion404A prevents it from being positioned further within the groove 403without contacting and interacting with the workpiece 402. As a result,the tip 408A is spaced excessively far from the bottom of the groove403, which results in poor arcing between the electrode 406A and theworkpiece 402, thereby resulting in a poor filler metal deposition rateand poor weld quality. Accordingly, the conventional stick-out length416A of the electrode assembly 400A prevents the electrode assembly 400Afrom forming high-quality welds within deep and/or narrow grooves. Incontrast, when the electrode assembly 400B is positioned over theworkpiece 402B such that the tip 408B is within the groove 403, theincreased stick-out length of the assembly 400B allows for the tip 408Bto be adjacent to the bottom of the groove. The reduced distance betweenthe tip 408B and the bottom of the groover 403 results in better arcingbetween the electrode 406B and the workpiece 402. Accordingly, inaddition to improving weld quality and deposition rates due to allowingfor additional preheating of the electrode prior to arcing, LSO SAWtechniques also allow for the deposition of filler metal into the deeperand narrower grooves than conventional SAW techniques.

According to various embodiments, the LSO SAW electrode assemblies arecapable of achieving significantly higher deposition rates compared toconventional SAW electrode assemblies for the same current. During thewelding process, current is transferred into the electrode by thecontact tip at a specific amperage and voltage. As the current flowsthrough the electrode toward the tip of the electrode, the voltage dropsand the electrode heats up. At the tip of the electrode, the currentarcs to the workpiece. For LSO SAW assemblies, the increased length ofthe electrode results in a higher fraction of the total voltage dropoccurring within the electrode than in conventional SAW assemblies. Insome embodiments, the LSO SAW assemblies can be configured such that thevoltage drop between the contact tip and the tip of the consumableelectrode is at least 5%, at least 10%, at least 15%, or at least 20%(or is a value in a range defined by any of these values) of a totalvoltage drop across the total CTWD. In other embodiments, the electrodeassembly is configured such that the voltage drop between the contacttip and the tip of the consumable electrode represents at least 1/30 ofthe total voltage drop across the CTWD, 1/15 of the total voltage dropacross the CTWD, 1/10 of the total voltage drop across the CTWD, 1/7 ofthe total voltage drop across the CTWD, ⅕ of the total voltage dropacross the CTWD, or a value in a range defined by any of these values.For example, in a conventional SAW electrode assembly where the totalvoltage drop along the CTWD is 30V, only about 1V of that total voltagedrop may occur within the consumable electrode while the rest (about29V) may drop across the arc length. In contrast, for an LSO SAW systemof the same total voltage drop of 30V, about 4V of may drop occursacross the CTWD while the rest (about 26V) may drop cross the arclength. The increased voltage drop through the longer electrode resultsin the electrode being heated to a higher temperature than the electrodein a conventional SAW configuration and, as a result, the depositionrate increases.

Experiments have shown that the deposition rate per current for LSO SAWassemblies can exceed 0.05 lbs./hr./A, 0.06 lbs./hr./A, 0.07 lbs./hr./A,0.08 lbs./hr./A, or a value in range defined by any of these valuesduring welding. FIG. 5 illustrates an experimental comparison ofdeposition rates versus current for both conventional SAW assemblies andLSO SAW assemblies, where the dashed lines represent the depositionrates for conventional SAW assemblies and the solid lines represent thedeposition rates for the LSO SAW assemblies. In this experiment, theCTWD for the conventional SAW assembly was 1.25″, the CTWD for the LSOSAW assembly was 5″, and the diameter of the electrode was 5/32″. Threedifferent power delivery methods were used: positive constant DC power,balanced square wave AC power, and 25% balanced square wave AC power.For the LSO SAW assemblies, a deposition rate exceeding 35 lbs./hr. canbe achieved with current less than about 900 A, 850 A, 800 A, 750 A, 700A, or in a range defined by any of these values, e.g., at about 700A-750 A. For conventional SAW electrode assemblies, however, similardeposition rates are only projected to be achieved at a currentexceeding about 900 A. Advantageously, the improvement in depositionrate over conventional SAW electrodes increases at higher current, asJoule heating (FR) varies as a square of current. That is, the relativeimprovement in deposition rate is projected to increase with increasingcurrent.

In LSO SAW systems, the consumable electrode (e.g., electrodes 306B,406B) extends beyond the end of the head portion (e.g., head portions304B, 404B) such that the arcing tip (e.g., tips 308B, 408B) is visible.As previously discussed, the portion of the electrode that extendsbeyond the contact tip portion is referred to as the electricalstick-out. In some embodiments, the electrical stick-out is measuredbased on the diameter of the electrode. The length of the electricalstick-out in SAW can depend on the type of steel being welded, e.g.,whether the steel being welded is a low alloy steel containing less thanabout 8 wt. % of non-iron elements or a high alloy steel containinggreater than about 8 wt. % of non-iron elements. In conventional SAW forwelding low and mild steel, the electrical stick-out length can beapproximately 7-10 times the diameter of the electrode. In conventionalSAW for welding high alloy steel, the electrical stick-out length can beapproximately 3-5 times the diameter of the electrode. For example, inembodiments where the diameter of the electrode is 5/32″, the visiblestick-out length can be approximately 1-1.5 inches. In contrast, in LSOSAW according to various embodiments, a stick out-to-diameter ratio, ora ratio between an electrical stick-out distance, measured between acontact tip portion disposed at an end of the head portion and thearcing tip of the consumable electrode, and a diameter of the electrodeexceeds 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or has a value in a rangedefined by any of these values. For example, these ratios can beobtained by electrical stick-out distance exceeding 125 mm, 130 mm, 135mm, 140 mm, 145 mm, 150 mm, 155 mm, 160 mm, 165 mm or a value in a rangedefined by any of these values, and a diameter of the electrode havingany value between 2.5 mm and 5.0 mm. For instance, for an electricalstick-out length of 155 mm and an electrode diameter of 3.2 mm, thestick out-to-diameter ratio is about 48, whereas for an electricalstick-out length of 125 mm and an electrode diameter of 4.0 mm, thestick-out-to-diameter ratio is about 31.

While increased stick-out length can advantageously provide certainadvantages, such as higher deposition rate, various problems can arisefor stick-out lengths exceeding, e.g., 25 mm, when conventionalelectrode assemblies are used. For example, the heated wire can move outof alignment and wander in the welding groove as the stick-out distanceincreases. This can pose a problem especially in welding deep and narrowgrooves that may be used to minimize time and cost of joining thicksections, as LSO welding electrode assemblies can be too bulky to reachthe bottom of the groove. To address this and other challenges, someelectrode assemblies include an extension portion that serves as aninsulated guide for the electrode. The extension portion provides, amongother things, electrical and thermal insulation as well as mechanicalrigidity to the heated electrode. However, some extensions may not besuitable for some applications, e.g., for filling narrow and deepgrooves such as a triangular or U-shaped groove having a depth exceeding4 inches and having an angle of an apex that is 16 degrees or less. Somedesigns of the electrode assemblies that include extension portions maybe insufficient with respect to one or more of: optimized vertical andlateral dimensions, thermal and electrical insulation, arc instabilitycaused by magnetic materials and compact flux delivery. In contrastvarious embodiments of the electrode assembly for submerged arc weldingdescribed herein address these and other needs.

Long Stick-Out Electrode Assembly with Covered Insulating ExtensionPortion

Disclosed herein are various electrode assemblies for improved LSO SAWand method of manufacturing and using the same. FIGS. 6A and 6B depictan example electrode assembly 600 configured for long stick-outsubmerged arc welding, according to various embodiments. The electrodeassembly 600 according to various embodiments comprises a head portion602, an extension portion 604, and a bracket 612. The head portion 602and extension portion 604 are arranged serially and configured to feed aconsumable electrode 606 therethrough. The bracket 612 is fixedlyattached to and electrically insulated from the head portion 602 and theextension portion 604 and is configured to securely hold the extensionportion 604 such that the extension portion 604 remains aligned with thehead portion 602. The electrode 606 includes a tip configured to bepositioned adjacent to a workpiece during the welding process. The headportion 602 includes a contact tip 610 that is in electrical contactwith the electrode 606 and is configured to provide power to theelectrode 606 during welding. The consumable electrode 606 is fedthrough the head portion 602 with a wire guide and exits at the contacttip 610. The consumable electrode 606 is subsequently fed through theextension portion 604, which is elongated in a wire feed direction.During SAW, the head portion 602 is disposed to be distal to the tip 608of the electrode and the extension portion 604 is disposed to beproximal to the tip 608.

In the illustrated example, the serially arranged head portion 602 andextension portion 604 are arranged serially and do not have verticallyoverlapping portions. While in the illustrated configuration the headportion 602 and the extension portion 604 are physically separated andexposes the consumable electrode 606 therebetween, embodiments are notso limited. In other arrangements, the contact tip portion and theextension portion may contact each other. It will be appreciated that,in the illustrated embodiment, because of the serial arrangement of thehead portion 602 and the extension portion 604, the contact tip 610 andthe extension portion 604 are also serially arranged, such that noportion of the extension portion 604 overlaps the contact tip 610.Further, the outer surface of the extension portion 604 forms theoutermost surface of the electrode assembly 600 adjacent the arcing tipof the exposed consumable electrode 606.

In some embodiments, the electrode assembly 600 also includes a fluxdelivery system 614. The flux delivery system 614 is configured todeposit flux onto the workpiece during the SAW process. Advantageously,the flux delivery system 614 is configured such that the flux deliverysystem 614 does not limit the dimensions of a groove of a workpiece theextension portion 604 is capable of being inserted into. In theillustrated embodiment, the flux delivery system 614 is fixedly attachedto the extension portion 604 with the bracket 612. In other embodiments,however, the flux delivery system 614 can be fixedly attached to theextension portion 604 in some other way. In still other embodiments, theflux delivery system 614 may not be fixedly attached to the extensionportion 604. Instead, in some embodiments, the flux delivery system 614may be fixedly attached to some other portion of the electrode assembly600 or may not be attached to any portion of the electrode assembly 600.Additionally, because the electrode assembly 600 is configured for SAW,embodiments of the electrode assembly 600 are configured to be used inSAW systems without the use of a shielding gas.

The extension portion 604 is configured to electrically insulate theconsumable electrode 606 from a work piece during welding with aninsulating sleeve formed of a solid insulating material, e.g., a ceramicmaterial, surrounding the consumable electrode. In some implementations,the solid insulating material may be a composite or layered insulator,e.g., a composite or layered ceramic. During welding, the consumablewelding electrode 606 is preheated in the insulated extension portion604 by Joule heating, prior to being melted at the arcing tip 608 of theconsumable electrode 606. In some embodiments, the electrode assembly608 is configured to heat the consumable electrode within the extensionportion to a temperature up to 600° C., up to 700° C., up to 800° C., upto 900° C., or to a temperature in a range defined by any of thesevalues.

FIG. 6C depicts the electrode assembly 600 positioned within a groove616 formed in a workpiece 618. In various embodiments, the extensionportion 604 is configured to electrically insulate the consumableelectrode 606 from the workpiece 618 and has a shape, length and alateral dimension such that the extension portion 604 is configured tobe capable of being inserted into narrow grooves 616 as shown in FIG.6C. The insulating sleeve formed of a solid insulating material such asa ceramic material surrounding the consumable electrode 606 inside theextension portion 604 allows the lateral dimension of the extensionportion 604 to be significantly reduced without increasing thelikelihood of shorting the electrode and the workpiece. For example, insome embodiments, while the contact tip 610 can have a width up to 30 mm(or about 1.18 inches), the extension portion 604 can have a width ofabout 16 mm (or about 0.79 inches). Additionally, in some embodiments,the extension portion can have a length of 110 mm (or about 4.33inches). In these embodiments, the head portion 602 is spacedsufficiently far apart from the tip 608 of the electrode such that,during welding, the wider head portion 602 can positioned outside of thegroove 616 in the workpiece 618 while the narrower extension portion 604is disposed within the groove. As a result, the narrower extensionportion 604 is configured to not contact a sidewall of narrow grooves616 such as a triangular trench having a depth exceeding 4 inches, 5inches, 6 inches, 7 inches, or a value in a range defined by any ofthese values, and having an angle 620 of an apex that is less than 16degrees, 12 degrees, 10 degrees, 8 degrees, 6 degrees, or a value in arange defined by any of these values, while the tip 608 of theconsumable electrode 606 contacts the apex. It will be appreciated thatshallower the groove 616, the narrower the apex angle 620 can be. Forexample, the relationship may follow an example dependence such as thatshown in TABLE 1, without limitation. It will be appreciated that thegrooves or trenches may not have a triangular shape in cross section.Instead, some grooves may have, e.g., a rectangular or taperedrectangular shape. In these geometries, the “apex” angle 620 or theacceptance angle can be defined by an arctan of a width over depth ofthe trench.

TABLE 1 Groove Depth Apex Angle >2 in.  <8 deg. >3 in. <10 deg. >4 in.<12 deg.

In various embodiments, the extension portion is configured toelectrically insulate the consumable electrode from a work piece duringwelding while having an outer surface formed of a substantiallynon-magnetic material surrounding the consumable electrode. FIG. 7Adepicts an extension portion 700 and FIG. 7B depicts an exploded view ofthe extension portion 700. The extension portion 700 has opposing firstand second ends 702A, 702B and an opening 704 that extends between thefirst end 702A and the second end 702B. The extension portion 700further includes an envelope or nozzle body 706, an insulating sleeve708 disposed within the nozzle body 706, a c-clamp 710, and a nut 712.As will be discussed in greater detail elsewhere in the application, theinsulating sleeve 708 can have a generally cylindrical shape thatdefines the opening 704. The extension portion 700 is configured to befixedly attached to the head portion of an electrode assembly (e.g.,head portion 602 of electrode assembly 600 shown in FIGS. 6A-6C) suchthat the first end 702A is proximal to a contact tip within the headportion (e.g., contact tip 610) while the second end 702B is distal tothe contact tip. During the SAW process, the extension portion 700receives a consumable electrode (e.g., electrode 606 in FIGS. 6-6C) fromthe head portion and the electrode is disposed within the opening 704such that it extends between the first and second ends 702A, 702B of theextension portion 700. The insulating sleeve 708 is configured todirectly surround the consumable electrode without an interveningstructure or feature other than air.

In some embodiments, the extension portion 700 is fixedly attached tothe head portion with a bracket (e.g., bracket 612 in FIG. 6B) and thec-clamp 710 and nut 712 can be used to fixedly attach the extensionportion 700 to the bracket. However, this is merely one possible methodof fixedly attaching the extension portion 700 to the head portion andother suitable attachment mechanisms may be used instead. For example,in some embodiments, the extension portion 700 can be fixedly attachedto the bracket by welding the nozzle body 706 to the bracket. In theseembodiments, the extension portion 700 may not include the c-clamp 710and nut 712.

FIG. 7C is a perspective view of the envelope or nozzle body 706 andFIG. 7D is a cross-sectional view of the envelope or nozzle body 706taken along line A-A. The envelope or nozzle body 706 includes first andsecond ends 714A, 714B and a cavity or opening 716 that extends betweenthe first and second ends 714A, 714B and that is configured to receiveand house the insulating sleeve 708 therein. In various embodiments, theenvelope or nozzle body 706 can have a generally cylindrical shapehaving at least a portion that tapers inwards toward the second end714B. As will be discussed in greater detail elsewhere in theapplication, the tapered second end 714 advantageously allows multipleelectrode assemblies to be positioned more closely adjacent to eachother when used in a multi-arc configuration.

According to embodiments, the envelope or nozzle body 706 functions asan outer envelope for the extension portion 700 and can be formed of anon-magnetic material. When the envelope 706 is formed of a magneticmaterial, it can exert or modify the magnetic field in its vicinity,thereby degrading, modifying or blowing the arc plasma. Furthermore, amagnetic material can become magnetized or demagnetized over time,thereby resulting in a drift of the arc characteristics. To addressthese and other concerns, in some embodiments, the envelope 706 isformed of a non-magnetic material such as a non-magnetic steel. Asdescribed herein, a non-magnetic steel refers to a steel having a lowferrite content and a high austenitic content, e.g., a steel having aferrite number (FN) less than about 8. For example, the non-magneticsteel can be a high Cr-content steel, such as a stainless steel. Formingthe nozzle body 706 out of a non-magnetic material advantageouslyimproves the consistency of the magnetic field around the consumableelectrode and reduces arc instability and welding defects. Thenon-magnetic material also reduces any instability of the weldingparameters that may be caused by magnetization of the extension portion706 over time.

FIG. 7E is a perspective view of the insulating sleeve 708 and FIG. 7Fis a cross-sectional view of the insulating sleeve 708 taken along theline B-B. The insulating sleeve 708 includes first and second ends 718A,718B and has a generally cylindrical shape that forms the opening 704through which the consumable electrode passes. In representativeembodiments, the insulating sleeve 708 is formed of an insulatingmaterial that thermally and electrically insulates the electrode as itpasses through the extension portion 700. Advantageously, forming theinsulating sleeve 708 from an insulating material allows for increasedpreheating of the consumable electrode during the welding processbecause the insulating material reduces dissipation of heat generated bythe preheating electrode to the surrounding. Instead, the insulatingsleeve 708 increases the relative amount of heat that remains trappedwithin the extension portion 700, thereby increasing the efficiency ofpreheating of the electrode, which in turn results in higher depositionand melt off rates and higher productivity.

Furthermore, the insulating sleeve 708 allows the extension portion 700to contact groove sidewalls of the workpiece without risking anelectrical short between the electrode and the workpiece. When theelectrode is heated to above-described temperatures during welding, theinsulating material may lose some of its resistivity. To ensure thatvoltage drop caused by such contact remains relatively low, the solidinsulating material is formed of an insulating material and configuredto sustain a voltage difference of at least 5V, 10V, 15V, 20V, 25V or avalue in range defined by any of these values, without substantiallyconducting when an outer surface of the extension portion 700 contactsthe workpiece.

In some embodiments, the insulating sleeve 708 is formed from aninsulating ceramic material. For example, in some embodiments, theinsulating sleeve 708 is formed of alumina (Al₂O₃) or silicon carbide(SiC). In other embodiments, however, other insulating materials can beused. For example, in some embodiments, the insulating sleeve 708comprises silicon nitride, magnesia-stabilized zirconia,yttria-stabilized zirconia, magnesium oxide, or a zirconia-toughenedalumina. The ceramic insulating sleeve 708 can be manufactured usingvarious methods such as powder pressing, cold isostatic pressing, hotpressing, injection molding and slip casting. Additionally, in someembodiments, the ceramic insulating sleeve 708 is not machined.

In various embodiments, the extension portion 700 is configured toelectrically insulate the consumable electrode from a work piece and hasa shape, length and a lateral dimension such that the length of theelectrical stick-out between the contact tip portion (e.g., contact tip610 shown in FIGS. 6A-6C) and the tip of the consumable electrode (e.g.electrode 606 shown in FIGS. 6A-6C) is substantially longer than inconventional SAW electrode assemblies. For example, in some embodiments,the extension portion 700 has a suitable length for supporting theelectrical stick out length described herein. For example, as describedabove, the electrical stick out can be 125 mm or longer. Accordingly,the extension portion 700 has a length that can be up to approximately110 mm. The visible stick-out, which corresponds to the portion of theconsumable electrode that extends beyond the extension portion 700, canhave a length that is a difference between these two values. With thisconfiguration, the length of the electrical stick-out, which includesthe portions of the electrode within the extension portion 700 and thevisible stick-out, can be at least as large as the sum of the visiblestick-out length and the length of the extension portion 700.Accordingly, during welding, the extension portion 700 can cause theelectrical-stick-out to exceed 100 mm, 125 mm, 150 mm, 175 mm, or alength in a range defined by any of these values, e.g., 150-160 mm. Forexample, in some embodiments, the electrode assemblies can have anelectrical stick-out of about 155 mm. Advantageously, the longerelectrical stick-out substantially improves the deposition rate for agiven current density, due to longer Joule-heated region provided by theextension portion 700.

In addition, the insulating sleeve 708 enables, among other things, theshape and width of the extension portion 700 to be optimized forinserting the extension portion 700 into narrow grooves as describedherein. According to various embodiments, the maximum width of theextension portion 700 at upper, untampered portions thereof can be lessthan 20 mm, 18 mm, 16 mm, 14 mm, 12 mm, or a value in a range defined byany of these values. Additionally, in some embodiments, the extensionportion 700 can have a generally cylindrical shape having at least aportion that tapers inward towards the second end 714B such that thewidth of the extension portion 700 at the second end 714B is less than amaximum width of the extension portion 700. In the illustratedconfiguration, the extension portion 700 is tapered at a lower portionthereof, while an upper portion of the extension portion 700 issubstantially straight. However, embodiments are not so limited and inother configurations, the extension portion 700 can be taperedsubstantially throughout its entire length. For example, in someembodiments, the extension portion 700 can have a maximum width of 16 mmthat tapers to a width of 10.8 mm at the second end 714B. In otherembodiments, however, the tapered second end 714B can have a differentwidth. For example, in some embodiments, the width of the extensionportion 700 at the second end 714B can be 12 mm, 11 mm, 10 mm, 9 mm, 8mm, less then 8 mm, or a value in a range defined by any of thesevalues. In some embodiments, the extension portion 700 can taper inwardsat the second end 714B at an angle of 2°, 3°, 4°, 5°, 6°, 7°, 8°, morethan 8°, or a value in a range defined by any of these values. Forillustrative purposes only, roughly one third of the length of theillustrated extension portion 700 is tapered. However, it will beappreciated that any suitable fraction of the length may be tapered,including substantially the entire length, e.g., greater than 20%, 40%,60% or 80%, 100%, or a value in a range defined by any of these values.It will be further appreciated that the tapered sidewall may not bestraight, but the degree of tapering may vary with length. For example,the degree of tapering may vary, e.g., continuously or discontinuously,throughout the tapered portion. As configured, the extension portion 700can be configured to not touch the sidewalls of a narrow groove such asa generally triangular trench as described elsewhere in the application.Any portion of the tapered portion can be configured such that tangentsof the exterior sidewalls form a triangle or a cone having an angle ofan apex that is less than 16 degrees, 12 degrees, 10 degrees, 8 degrees,6 degrees, or a value in a range defined by any of these values.Advantageously, the shape and dimensions of the extension portion 700 asdescribed can enable its insertion into narrow grooves withoutcontacting the sidewalls thereof. Additionally, as will be discussed ingreater detail elsewhere in the application, the tapered second end 714Badvantageously allows multiple electrode assemblies to be positionedmore closely adjacent to each other when use din a multi-arcconfiguration.

Another benefit of the electrode assembly 700 is that flux-to-wireconsumption ratio is lower than conventional SAW assemblies because theelectrode deposition rate increases while the flux consumption remainsconstant.

As previously discussed, the insulating sleeve 708 is disposed withinthe envelope or nozzle body 706. In some embodiments, the insulatingsleeve 708 is placed within the nozzle body 706 without an adhesive orother material such that any gaps that may exist between the innersurfaces of the nozzle body 706 and the outer surfaces of the insulatingsleeve 708 are filled with air and the insulating sleeve 708 can move orrotate relative to the envelope or nozzle body 706. In otherembodiments, however, the insulating sleeve 708 may be securely attachedto the nozzle body 706 with an intervening material. For example, insome embodiments, the insulating sleeve 608 is disposed within thenozzle body 706 with a suitable sealant or adhesive. In theseembodiments, the suitable sealant may be disposed between the nozzlebody 606 and the insulating sleeve 708 such that the sealant fills anygap that may exist between the inner surfaces of the nozzle body 706 andthe outer surfaces of the insulating sleeve such that the insulatingnozzle 708 is immobilized with respect to the nozzle body 706. In theseembodiments, the suitable sealant may be a relatively soft material andmay serve as a shock absorbing layer between the insulating sleeve 708and the nozzle body 706 such that cracking of the insulating sleeve 708under mechanical or thermal stress is suppressed or prevented. In otherembodiments, a different material can be used to securely attach theinsulating sleeve 708 within the nozzle body 706. For example, in someembodiments, the insulating sleeve 708 and the envelope or nozzle body706 may be attached using a brazed metallic joint. In other embodiments,the insulating sleeve 708 and the envelope or nozzle body 706 may beattached using a non-metallic sealant or adhesive such as a polymericadhesive material or epoxy.

FIG. 8 is a top-down cross-sectional view of an extension portion 800.The extension portion 800 includes an opening 802 through which aconsumable electrode is configured to slidingly pass through, anenvelope or nozzle body 804, and an insulating sleeve 806 disposedwithin the envelope or nozzle body 804. In the illustrated embodiment,the insulating sleeve 806 is attached to the envelope 804 using asealant layer 808. The sealant layer 808 is formed from a suitablesealant that may be a relatively soft material and may serve as a shockabsorbing layer between the insulating sleeve 806 and the envelope ornozzle body 804 such that cracking of the insulating sleeve 806 undermechanical or thermal stress is suppressed or prevented. Furthermore,even when the insulating sleeve 806 cracks, the suitable sealant caneffectively prevent loose pieces form coming off and falling on theworkpiece. In some implementations, insulating sleeve 806 is brazed intothe envelope or nozzle body 804 and the suitable sealant comprises asuitable brazing material. The suitable brazing material has a meltingtemperature that is substantially lower than a melting temperature ofthe envelope or nozzle body 804. Without limitation, suitable brazingmetals include copper-based alloy, e.g., Cu/Sn alloys. In some otherimplementations the suitable sealant comprises a suitable glass sealantthat has a glass working temperature that is substantially lower than amelting temperature of the metallic sheaths. Without limitation,suitable sealants include a doped silica, e.g., a doped aluminosilicateglass or a heavily doped sodium silicate glass. Other sealants may bepossible, e.g., high-temperature epoxy that can withstand the outertemperature of the insulating sleeve. Advantageously, securing theinsulating sleeve 806 to the envelope 804 using a suitable sealantimproves the durability, reliability and lifespan of the extensionportion 800.

One additional advantage of utilizing the relatively narrow extensionportion as described herein is that it facilitates using multipleelectrode assemblies in multi-arc set-ups. When welding large pieces ofmetal together, it is sometimes desirable to use multiple electrodeassemblies at the same time to further increase the filler metaldeposition rate. During multi-arc welding, the tips of multipleelectrodes should be positioned closely adjacent to each other such thateach of the electrode tips is disposed within the same weld pool.However, it is often difficult to use conventional SAW electrodeassemblies in a multi-arc set-up. This is because the large diameter ofthe head portions (e.g., head portions 204 (FIG. 2 ), 304A (FIG. 3A),304B (FIG. 3B)) of conventional electrode assemblies makes it difficultfor multiple electrode assemblies to be placed sufficiently close toeach other to facilitate multi-arc welding. Additionally, the shortlength of the electrode stick-out portions (e.g., stick-out portions316A, 416A) used in conventional SAW assemblies may require that thewelding torches be arranged at a high angle with respect to each otherto allow for the arcing tips of the respective electrodes to besufficiently close to each other to be positioned within the same weldpool. Accordingly, it is challenging to use conventional SAW electrodeassemblies in multi-arc set-ups because the large size of the headportions and the short stick-out length limit the number of electrodeassemblies that can be used in multi-arc set-up while also making itdifficult to position the torches when trying to weld within a groove.These and other challenges can be mitigated with extension portionsaccording to embodiments having relatively narrow extension portions, asdescribed herein.

FIG. 9A depicts a multi-arc SAW system 900A having first and secondelectrode assemblies 902A, 902B. The first electrode assembly 902Aincludes a head portion 904A having a contact tip 906A, an electrode908A having a tip 910A, an extension portion 912A, and a flux deliverysystem 914A. Similarly, the electrode assembly 902B includes a headportion 904B having a contact tip 906B, an electrode 908B having a tip910B, an extension portion 912B, and a flux delivery system 914B. Theelectrode assemblies 902A, 902B are generally similar to the electrodeassembly 600 described above in connection with FIGS. 6A-6C and theextension portions 912A, 912B may be generally similar to the extensionportions 700 and 800 described above in connection with FIGS. 7A-7F andFIG. 8 . As previously discussed, while the contact tips 906A, 906B canhave a width up to 30 mm (or about 1.18 inches), the extension portions912A, 912B can have a width of about 16 mm (or about 0.79 inches) and alength of about 110 mm (or about 4.33 inches), which allows for theelectrode assemblies 902A, 904A to each have an electrical stick-outgreater than 125 mm (or about 4.92 inches).

With this configuration, the first and second electrode assemblies 902A,902B can be positioned such that a distance 916 between the tips 910A,910B of the electrodes 908A, 908B is sufficiently small to allow forefficient multi-arc welding. Specifically, the shape, length, and widthof the extension portions 912A, 912B as described herein allows for theextension portions 912A, 912B to be simultaneously positioned withinnarrow and deep grooves such that the tips 910A, 910B are disposedwithin the same weld pool during the SAW process without the extensionportions contacting the sidewalls of the grooves. For example, in someembodiments, the first and second electrode assemblies 902A, 902B can bepositioned such that, during welding, the distance 916 between the tips910A, 910B is 15 mm while the angle 920 between the electrode assemblies902A, 902B is 20 degrees. However, this is only one example. In otherembodiments, the electrode assemblies 902A, 902B can be positioned suchthat, during multi-arc welding operations, the distance 916 between thetips 910A, 910B is less than 30 mm, 25 mm, 20 mm, 15 mm, or a value in arange defined by any one of these values, and the electrode assemblies902A, 902B are oriented such that the angle 920 between the electrodeassemblies 902A, 902B is less than 40 degrees, 35 degrees, 30 degrees,25 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, or a value ina range defined by any one of these values.

FIG. 9B depicts another multi-arc SAW system 900B having three electrodeassemblies 902A, 902B, and 902C, where each of the electrode assemblies902A, 902B, and 902C is configured as described above in connection withFIG. 9A. The size, shape, and width of the extension portions 912A,912B, 912C for the electrode assemblies 902A, 902B, 902C as describedherein allows for extension portions 912A, 912B, 912C to besimultaneously positioned with narrow and deep grooves such that theelectrode tips 910A, 910B, 910C are all disposed within the same weldpool during the SAW process without the extension portions contactingthe sidewalls of the groove. For example, in the illustrated embodiment,the electrode assemblies 902A, 902B, 902C are positioned such that thedistance 916 between the first and second tips 910A, 910B is 26 mm, thedistance 918 between the second and third tips 910B, 910C are spacedapart from each other by 15 mm, the angle 920 between the first andsecond electrode assemblies 902A, 902B is 5 degrees, and the angle 922between the second and third electrode assemblies 902B, 902C is 20degrees. However, this is only an example. In other embodiments, theelectrode assemblies 902A, 902B, 902C can be positioned such that,during multi-arc welding operations, the distances 916, 918 betweenadjacent tips 910A, 910B, 910C is less than 30 mm, 25 mm, 20 mm, 15 mm,or a value in a range defined by any one of these values, and electrodeassemblies 902A, 902B, 902C are oriented such that the angles 920, 922between adjacent electrode assemblies 902A, 902B, 902C is less than 40degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10degrees, 5 degrees, or a value in a range defined by any one of thesevalues.

Still referring to FIGS. 9A and 9B, according to embodiments, each ofthe first, second (and third) electrode assemblies 902A, 902B (and 902C)is configured such that each of the multiple electrodes independentlyreceives power from a dedicated power supply (e.g., power supply 108shown in FIG. 1 ). With this arrangement, each of the electrodeassemblies can receive an independently controlled power, which allowsfor more consistent and efficient deposition of filler metal.Additionally, the current provided to each electrode assemblies can bevaried for each electrode assembly such that individual electrodeassemblies can receive different currents. In other embodiments,however, each of the electrode assemblies used in a multi-arc set-up canbe coupled together in parallel such that each of the electrodeassemblies shares the same current.

ADDITIONAL EXAMPLES

1. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece during        welding with a solid insulating material surrounding the        consumable electrode.

2. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the extension        portion is configured to capable of not contacting a sidewall of        a triangular trench having a depth exceeding 4 inches and having        an angle of an apex that is less than 16 degrees while the tip        of the consumable electrode contacts the apex.

3. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece during        welding while having an outer surface formed of a substantially        non-magnetic material surrounding the consumable electrode.

4. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that a        contact-to-work distance (CTWD) between the head portion and the        tip of the consumable electrode during welding exceeds 125 mm.

5. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece during        welding; and    -   a flux delivery system fixedly attached to the extension portion        and configured such that the flux delivery system does not limit        dimensions of a groove of a workpiece the extension portion is        capable of being inserted into.

6. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the electrode        assembly is configured to achieve a deposition rate per current        exceeding 0.05 lbs./hr./A during welding.

7. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the electrode        assembly is configured to achieve a deposition rate exceeding 35        lbs./hr. at a current less than 900 A during welding.

8. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the electrode        assembly is configured to drop at least 5% of a total voltage        drop cross a contact-to-work distance (CTWD) between the head        portion and the tip of the consumable electrode.

9. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the electrode        assembly is configured to drop at fraction exceeding 2V of a        total voltage drop cross a contact-to-work distance (CTWD)        between the head portion and the tip of the consumable        electrode.

10. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece and has a        shape, length and a lateral dimension such that the electrode        assembly is configured to heat the consumable electrode by Joule        heating within the extension portion to a temperature up to 800°        C.

11. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is configured to electrically        insulate the consumable electrode from a work piece during        welding with a solid insulating material, wherein the solid        insulating material has sufficient resistance such that it is        configured to sustain a voltage difference of at least 5V        without substantially conducting when an outer surface of the        extension portion contacts the work piece.

12. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion comprises an insulating tip        portion formed of a solid insulating material configured to        electrically insulate the consumable electrode from a work piece        during welding by surrounding the consumable electrode.

13. The electrode assembly according to any of the above examples,wherein the solid insulating material comprises a ceramic material.

14. The electrode assembly according to any of the above examples,wherein the solid insulating material comprises an insulating sleeveconfigured to pass the consumable electrode therethrough.

15. The electrode assembly of any one of the above examples, wherein theextension portion is formed of a material selected from the groupconsisting of silicon nitride, magnesia-stabilized zirconia,yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina ora zirconia-toughened alumina.

16. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that the extension portion is configured to be capable ofnot contacting a sidewall of a triangular trench having a depthexceeding 4 inches and having an angle of an apex that is less than 16degrees while the tip of the consumable electrode contacts the apex.

17. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece during welding while having an outer surfaceformed of a substantially non-magnetic material surrounding theconsumable electrode.

18. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that a contact tip-to-work distance (CTWD) between thecontact tip portion and the tip of the consumable electrode duringwelding exceeds 125 mm.

19. The electrode assembly of any one of the above examples, furthercomprising a flux delivery system fixedly attached to the extensionportion and configured such that the flux delivery system does not limitdimensions of a groove of a workpiece the extension portion is capableof being inserted into.

20. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that the electrode assembly is configured to achieve adeposition rate per current exceeding 0.05 lbs./hr./A during welding.

21. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that the electrode assembly is configured to achieve adeposition rate exceeding 35 lbs./hr. at a current less than 900 Aduring welding.

22. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that the consumable electrode drops at least 5% of atotal voltage drop cross a contact-to-work distance (CTWD) between thecontact tip portion and the tip of the consumable electrode.

23. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that a stick-out portion of the consumable electrodedrops at least 2V of a total voltage drop cross a contact-to-workdistance (CTWD) between the contact tip portion and the tip of theconsumable electrode.

24. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece and has a shape, length and a lateraldimension such that the electrode assembly is configured to heat theconsumable electrode by Joule heating within the extension portion to atemperature up to 800° C.

25. The electrode assembly of any one of the above examples, wherein theextension portion is configured to electrically insulate the consumableelectrode from a work piece during welding with a solid insulatingsleeve, wherein the solid insulating sleeve has sufficient resistancesuch that it is configured to sustain a voltage difference of at least5V without substantially conducting when an outer surface of theextension portion contacts the work piece.

26. An electrode assembly for submerged arc welding (SAW), comprising:

-   -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein        during welding, the head portion is disposed to be distal to an        arcing tip of the consumable electrode and the extension portion        is disposed to be proximal to the arcing tip of the consumable        electrode,    -   wherein the extension portion is elongated in a wire feed        direction and configured to electrically insulate the consumable        electrode from a work piece during welding with an insulating        sleeve surrounding the consumable electrode, and    -   wherein the electrode assembly is configured such that, during        welding with the consumable electrode inserted therethrough, a        ratio between an electrical stick-out distance, measured between        a contact tip portion disposed at an end of the head portion and        the arcing tip of the consumable electrode, and a diameter of        the electrode exceeds 30.

27. The electrode assembly of example 26, wherein the extension portionhas an outer surface formed of a substantially non-magnetic materialsurrounding the insulating sleeve.

28. The electrode assembly of example 27, wherein the insulating sleeveis formed of a ceramic material that is enveloped by a substantiallynon-magnetic steel-based envelope forming the outer surface of theextension portion.

29. The electrode assembly of example 28, wherein the insulating sleeveand the non-magnetic steel-based envelope are held together by anadhesive layer.

30. The electrode assembly of example 29, wherein the adhesive layercomprises a brazed joint comprising a metallic filler material.

31. The electrode assembly of example 26, wherein the extension portionhas a length greater than 100 mm.

32. The electrode assembly of example 31 wherein the electrode assemblyis configured for the electrical stick-out distance exceeding 125 mm.

33. The electrode assembly of example 32, wherein the electrode assemblyis configured for the diameter of the electrode exceeding 3 mm.

34. The electrode assembly of example 32, wherein the extension portionhas an elongated shape such that, when fully inserted into a triangulartrench having a depth exceeding 4 inches and having an angle of an apexthat is less than 16 degrees such that the tip of the consumableelectrode contacts the apex of the triangular trench, no part of theextension portion contacts a sidewall of the triangular trench.

35. The electrode assembly of example 32, wherein the electrode assemblyis configured to achieve a deposition rate per current exceeding 0.05lbs./hr./A during welding.

36. The electrode assembly of example 32, wherein the electrode assemblyis configured to achieve a deposition rate exceeding 35 lbs./hr. at acurrent less than 900 A during welding.

37. The electrode assembly of example 32, wherein the electrode assemblyis configured to drop at least 5% of a total voltage drop across adistance between the head portion and the arcing tip of the consumableelectrode.

38. The electrode assembly of example 32, wherein the electrode assemblyis configured to heat the consumable electrode by Joule heating withinthe extension portion to a temperature up to 800° C.

39. The electrode assembly of example 26, wherein the insulating sleevehas sufficient resistance such that it is configured to sustain avoltage difference of at least 5V without substantially conducting whenan outer surface of the extension portion contacts the work piece.

40. The electrode assembly of example 39 wherein the insulating sleeveis formed of a ceramic material selected from the group consisting ofsilicon nitride, magnesia-stabilized zirconia, yttria-stabilizedzirconia, silicon carbide, magnesium oxide, alumina, or azirconia-toughened alumina.

41. The electrode assembly of example 26, further comprising:

-   -   a flux delivery system fixedly attached to the extension portion        and configured such that the flux delivery system does not limit        a lower limit of a width of a groove of a workpiece the        extension portion is capable of being inserted into.

42. An electrode assembly for submerged arc welding, comprising:

-   -   a head portion; and    -   an extension portion arranged serially with the head portion in        a wire feed direction, wherein the head portion and the        extension portion are configured to feed a consumable electrode        therethrough, wherein the extension portion is configured to be        disposed closer to an arcing tip of the consumable electrode        relative to the head portion and comprises:        -   an envelope formed of a nonmagnetic material; and        -   an insulating sleeve disposed within the envelope and            comprising a solid insulating material configured to            surround the consumable electrode.

43. The electrode assembly of example 42 wherein:

-   -   the extension portion comprises opposing first and second ends        separated in the wire feed direction,    -   the head portion comprises a contact tip portion configured to        apply a voltage and pass current to the consumable electrode and        configured to be proximal to the first end of the extension        portion and distal to the second end of the extension portion,    -   when the consumable electrode is fed through the electrode        assembly, an arcing tip of the consumable electrode is        configured to be proximal to the second end of the extension        portion and distal to the first end of the extension portion,        and    -   the extension portion is disposed between the arcing tip and the        contact tip portion.

44. The electrode assembly of example 43 wherein the electrode assemblyis configured for an electrical stick-out distance, measured between acontact tip portion disposed at an end of the head portion and thearcing tip of the consumable electrode, exceeding 125 mm.

45. The electrode assembly of example 44, wherein the electrode assemblyconfigured such that a ratio between an electrical stick-out distance,measured between a contact tip portion disposed at an end of the headportion and the arcing tip of the consumable electrode, and a diameterof the electrode exceeds 30.

46. The electrode assembly of example 42 wherein the solid insulatingmaterial comprises a ceramic material.

47. The electrode assembly of example 42 wherein the insulating sleeveis fixedly attached to the envelope by an adhesive layer.

48. The electrode assembly of example 47 wherein adhesive layercomprises a brazed metallic joint.

49. An extension portion configured for a submerged arc weldingelectrode assembly, the extension portion comprising:

-   -   an envelope formed of a nonmagnetic material; and    -   an insulating sleeve disposed within the envelope and comprising        a solid insulating material configured to surround a consumable        electrode,    -   wherein the extension portion is configured to be arranged        serially with a head portion of the electrode assembly and to        receive a consumable electrode from the head portion.

50. The extension portion of example 49, wherein the extension portionhas a length greater than 100 mm.

51. The extension portion of example 49, wherein the extension portionis configured for a diameter of the consumable electrode exceeding 3 mm.

52. The extension portion of example 51, wherein the extension portionis configured such that during welding with the consumable electrodeinserted therethrough, a ratio between an electrical stick-out distance,measured between a contact tip portion disposed at an end of the headportion and an arcing tip of the consumable electrode, and the diameterof the electrode exceeds 30.

53. The extension portion of example 49, wherein the insulating sleeveis formed of a ceramic material.

54. The extension portion of example 49, wherein the envelope is formedof a substantially non-magnetic steel-based material.

55. The extension portion of example 54, wherein the envelope is formedof a stainless steel.

56. The extension portion of example 49, wherein the insulating sleeveand the envelope are held together by an adhesive layer.

57. The extension portion of example 56, wherein the adhesive layercomprises a brazed joint comprising a metallic filler material.

58. A method of welding a workpiece, comprising:

-   -   providing a submerged arc welding electrode assembly, the        electrode assembly comprising:    -   a head portion and an extension portion arranged serially and        configured to feed a consumable electrode therethrough, wherein:        -   the head portion is disposed to be distal to an arcing tip            of the consumable electrode and the extension portion is            disposed to be proximal to the arcing tip of the consumable            electrode, and        -   the extension portion is configured to electrically insulate            the consumable electrode from a work piece during welding            with a solid insulating material surrounding the consumable            electrode;    -   positioning the electrode assembly over the workpiece such that        the arcing tip is adjacent to the workpiece;    -   adjusting the electrode assembly such that a distance between        the head portion and the arcing tip of the consumable electrode        during welding exceeds 125 mm; and    -   providing a current to the electrode assembly.

59. The method of example 58 wherein the extension portion has a lengthgreater than 100 mm

60. The method of example 58 wherein:

-   -   the workpiece comprises a triangular trench having a depth        exceeding 4 inches and having an angle of an apex that is less        than 16 degrees,    -   positioning the electrode assembly over the workpiece comprises        positioning the electrode assembly such that the extension        portion is within the groove and the arcing tip contacts the        apex.

61. The method of example 60, further comprising:

-   -   moving the electrode assembly through the groove without the        extension portion contacting a sidewall of the triangular trench        while the arcing tip contacts the apex.

62. The method of example 58 wherein the electrode assembly isconfigured to achieve a deposition rate per current exceeding 0.05lbs./hr./A.

63. The method of example 58 wherein the electrode assembly isconfigured to achieve a deposition rate exceeding 35 lbs./hr. at acurrent less than 900 A.

64. The method of example 58 wherein the electrode assembly isconfigured to drop at least 5% of a total voltage drop across a distancebetween the head portion and the arcing tip of the consumable electrode.

65. The method of example 58 wherein the electrode assembly isconfigured to heat the consumable electrode by Joule heating within theextension portion to a temperature up to 800° C. during welding.

66. A multi-arc welding system for submerged arc welding within a grooveon a workpiece, wherein the groove has a depth exceeding 4 inches and anangle of an apex that is less than 16 degrees, the system comprising:

-   -   a first electrode assembly, wherein the first electrode assembly        comprises:        -   a first head portion; and        -   a first extension portion arranged serially with the first            head portion, wherein the first head portion and the first            extension portion are configured to feed a first consumable            electrode therethrough, wherein the first extension portion            comprises a first nozzle body formed from a nonmagnetic            material and a first insulating sleeve disposed within the            nozzle body and comprising a solid insulating material            configured to surround the first consumable electrode; and a            second electrode assembly, wherein the second electrode            assembly comprises:        -   a second head portion; and        -   a second extension portion arranged serially with the second            head portion, wherein the second head portion and the second            extension portion are configured to feed a second consumable            electrode therethrough, wherein the second extension portion            comprises a second nozzle body formed from the nonmagnetic            material and a second insulating sleeve disposed within the            second nozzle body, wherein the second insulating sleeve            comprises the solid insulating material that is configured            to surround the second consumable electrode,    -   wherein, during welding, the first and second electrode        assemblies are configured to be positioned within the groove        such that tips of the first and second consumable electrodes are        closely adjacent to the apex of the groove and closely adjacent        to each other without the first and second extension portions        contacting a sidewall of the groove.

67. The system of example 66 wherein, during welding, the first andsecond electrode assemblies are configured to be positioned within thegroove such that a distance between the tips of the first and secondconsumable electrodes is less than 30 mm and an angle between the firstand second electrode assemblies is less than 40 degrees.

68. The system of example 66, further comprising:

-   -   a third electrode assembly, comprising:        -   a third head portion; and        -   a third extension portion arranged serially with the third            head portion,    -   wherein the third head portion and the third extension portion        are configured to feed a third consumable electrode        therethrough,    -   wherein the third extension portion comprises a third nozzle        body formed from the nonmagnetic material and a third insulating        sleeve disposed within the second nozzle body,    -   wherein the third insulating sleeve comprises the solid        insulating material that is configured to surround the second        consumable electrode, and    -   wherein, during welding, third electrode assembly is configured        to be positioned within the groove such that a tip of the third        consumable electrode is closely adjacent to the tips of the        first and second consumable electrodes without the third        extension portion contacting the sidewall of the groove.

69. The system of example 66, wherein:

-   -   the first electrode assembly comprises a first flux delivery        system securely attached to the first head portion,    -   the second electrode assembly comprises a second flux delivery        system securely attached to the second head portion,    -   the first and second flux delivery systems are configured to        deposit flux into the groove, and    -   during welding, the first and second flux delivery systems do        not contact the sidewall of the groove.

70. The system of example 66 wherein the first and second extensionportions each have a length greater than 100 mm.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,”“include,” “including” and the like are to be construed in an inclusivesense, as opposed to an exclusive or exhaustive sense; that is to say,in the sense of “including, but not limited to.” The word “coupled”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Likewise, the word “connected”, as generally used herein,refers to two or more elements that may be either directly connected, orconnected by way of one or more intermediate elements. Additionally, thewords “herein,” “above,” “below,” and words of similar import, when usedin this application, shall refer to this application as a whole and notto any particular portions of this application. Where the contextpermits, words in the above Detailed Description using the singular orplural number may also include the plural or singular number,respectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or whether these features,elements and/or states are included or are to be performed in anyparticular embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel apparatus, methods, andsystems described herein may be embodied in a variety of other forms;furthermore, various omissions, substitutions and changes in the form ofthe methods and systems described herein may be made without departingfrom the spirit of the disclosure. For example, while blocks arepresented in a given arrangement, alternative embodiments may performsimilar functionalities with different components and/or circuittopologies, and some blocks may be deleted, moved, added, subdivided,combined, and/or modified. Each of these blocks may be implemented in avariety of different ways. Any suitable combination of the elements andacts of the various embodiments described above can be combined toprovide further embodiments. The various features and processesdescribed above may be implemented independently of one another, or maybe combined in various ways. All possible combinations andsubcombinations of features of this disclosure are intended to fallwithin the scope of this disclosure.

1. An electrode assembly for submerged arc welding (SAW), comprising: ahead portion and an extension portion arranged serially and configuredto feed a consumable electrode therethrough, wherein during welding, thehead portion is disposed to be distal to an arcing tip of the consumableelectrode and the extension portion is disposed to be proximal to thearcing tip of the consumable electrode, wherein the extension portion iselongated in a wire feed direction and configured to electricallyinsulate the consumable electrode from a work piece during welding withan insulating sleeve surrounding the consumable electrode, and whereinthe electrode assembly is configured such that, during welding with theconsumable electrode inserted therethrough, a ratio between anelectrical stick-out distance, measured between a contact tip portiondisposed at an end of the head portion and the arcing tip of theconsumable electrode, and a diameter of the consumable electrode exceeds30.
 2. The electrode assembly of claim 1, wherein the extension portionhas an outer surface formed of a substantially non-magnetic materialsurrounding the insulating sleeve.
 3. The electrode assembly of claim 2,wherein the insulating sleeve is formed of a ceramic material that isenveloped by a substantially non-magnetic steel-based envelope formingthe outer surface of the extension portion.
 4. The electrode assembly ofclaim 3, wherein the insulating sleeve and the non-magnetic steel-basedenvelope are held together by an adhesive layer.
 5. (canceled)
 6. Theelectrode assembly of claim 1, wherein the extension portion has alength greater than 100 mm and wherein the electrode assembly isconfigured for the electrical stick-out distance exceeding 125 mm. 7.(canceled)
 8. (canceled)
 9. The electrode assembly of claim 6, whereinthe extension portion has an elongated shape such that, when fullyinserted into a triangular trench having a depth exceeding 4 inches andhaving an angle of an apex that is less than 16 degrees such that thetip of the consumable electrode contacts the apex of the triangulartrench, no part of the extension portion contacts a sidewall of thetriangular trench.
 10. The electrode assembly of claim 6, wherein theelectrode assembly is configured to achieve a deposition rate percurrent exceeding 0.05 lbs./hr./A during welding.
 11. The electrodeassembly of claim 6, wherein the electrode assembly is configured toachieve a deposition rate exceeding 35 lbs./hr. at a current less than900 A during welding.
 12. The electrode assembly of claim 6, wherein theelectrode assembly is configured to drop at least 5% of a total voltagedrop across a distance between the head portion and the arcing tip ofthe consumable electrode.
 13. The electrode assembly of claim 6, whereinthe electrode assembly is configured to heat the consumable electrode byJoule heating within the extension portion to a temperature up to 800°C.
 14. (canceled)
 15. The electrode assembly of claim 1 wherein theinsulating sleeve is formed of a ceramic material selected from thegroup consisting of silicon nitride, magnesia-stabilized zirconia,yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina,or a zirconia-toughened alumina.
 16. The electrode assembly of claim 1,further comprising: a flux delivery system fixedly attached to theextension portion and configured such that the flux delivery system doesnot limit a lower limit of a width of a groove of a workpiece theextension portion is capable of being inserted into.
 17. An electrodeassembly for submerged arc welding, comprising: a head portion; and anextension portion arranged serially with the head portion in a wire feeddirection, wherein the head portion and the extension portion areconfigured to feed a consumable electrode therethrough, wherein theextension portion is configured to be disposed closer to an arcing tipof the consumable electrode relative to the head portion and comprises:an envelope formed of a nonmagnetic material; and an insulating sleevedisposed within the envelope and comprising a solid insulating materialconfigured to surround the consumable electrode.
 18. The electrodeassembly of claim 17 wherein: the extension portion comprises opposingfirst and second ends separated in the wire feed direction, the headportion comprises a contact tip portion configured to apply a voltageand pass current to the consumable electrode and configured to beproximal to the first end of the extension portion and distal to thesecond end of the extension portion, when the consumable electrode isfed through the electrode assembly, an arcing tip of the consumableelectrode is configured to be proximal to the second end of theextension portion and distal to the first end of the extension portion,and the extension portion is disposed between the arcing tip and thecontact tip portion.
 19. The electrode assembly of claim 18 wherein theelectrode assembly is configured for an electrical stick-out distance,measured between a contact tip portion disposed at an end of the headportion and the arcing tip of the consumable electrode, exceeding 125mm.
 20. The electrode assembly of claim 19, wherein the electrodeassembly configured such that a ratio between an electrical stick-outdistance, measured between a contact tip portion disposed at an end ofthe head portion and the arcing tip of the consumable electrode, and adiameter of the electrode exceeds
 30. 21. The electrode assembly ofclaim 17, wherein the solid insulating material comprises a ceramicmaterial.
 22. The electrode assembly of claim 17, wherein the insulatingsleeve is fixedly attached to the envelope by an adhesive layer thatcomprises a brazed metallic joint.
 23. (canceled)
 24. An extensionportion configured for a submerged arc welding electrode assembly, theextension portion comprising: an envelope formed of a nonmagneticmaterial; and an insulating sleeve disposed within the envelope andcomprising a solid insulating material configured to surround aconsumable electrode, wherein the extension portion is configured to bearranged serially with a head portion of the electrode assembly and toreceive the consumable electrode from the head portion.
 25. Theextension portion of claim 24, wherein the extension portion has alength greater than 100 mm.
 26. The extension portion of claim 24,wherein the extension portion is configured for a diameter of theconsumable electrode exceeding 3 mm.
 27. The extension portion of claim26, wherein the extension portion is configured such that during weldingwith the consumable electrode inserted therethrough, a ratio between anelectrical stick-out distance, measured between a contact tip portiondisposed at an end of the head portion and an arcing tip of theconsumable electrode, and the diameter of the electrode exceeds
 30. 28.The extension portion of claim 24, wherein the insulating sleeve isformed of a ceramic material.
 29. The extension portion of claim 24,wherein the envelope is formed of a substantially non-magneticsteel-based material.
 30. (canceled)
 31. The extension portion of claim24, wherein the insulating sleeve and the envelope are held together byan adhesive layer.
 32. (canceled)